The importance of temperature in assessing iron pipe corrosion in water distribution systems

Temperature is expected to play a significant role in the corrosion of iron pipes in drinking water distribution systems. Temperature impacts many parameters that are critical to pipe corrosion including biological activity, physical properties of the solution, thermodynamic and physical properties of corrosion scale, and chemical rates. Moreover, variations in temperature and temperature gradients may give rise to new corrosion phenomena worthy of consideration by water treatment personnel.     

Multi-level screening of a proposed hazardous waste treatment and disposal facility site--a case study

A comprehensive environmental assessment (EA) is a pre-requisite before the site for developing a hazardous waste treatment and disposal facility (HWTDF) is selected. However, the resource limitations, especially for developing countries, often dictatethat the detailed EA be restricted to those sites, which are constraint free and have low hazard potentials. Thus, a preliminary screening exercise for assessing the suitability ofsite for developing the HWTDF needs to be carried out to avoid huge costs involved in detailed EA. While screening a HWTDF site,various factors such as present land use, ecologically sensitiveareas, geology and hydrogeology of the area, the quality and quantity of wastes, engineered safeguards, and the operationalprocedures that need to be adopted, are required to be addressed. In this paper, a multi-level screening criteria employing RemoteSensing, Constraint Mapping, Groundwater Pollution Potential Index (DRASTIC Index), and the Site Ranking was used to assess the suitability of a proposed site for the development of HWTDF.The study helped to identify various constraints at the proposedsite and their significance on the development of the HWTDF.     

Monitoring of Seasonal Vegetables for Pesticide Residues

Market samples (60) of six seasonal vegetables were monitoredduring 1996–1997 to determine the magnitude of pesticidalcontamination. The estimation of insecticide residuesrepresenting four major chemical groups i.e. organochlorine,organophosphorous, synthetic pyrethroid and carbamate, was doneby adopting a multiresidue analytical technique employingGC-ECD and GC-NPD systems with capillary columns. The testedsamples showed 100% contamination with low but measurableamounts of residues. Among the four chemical groups, theorganophosphates were dominant followed by organochlorines,synthetic pyrethroids and carbamates. About 23% of the samplesshowed contamination with organophosphorous compounds abovetheir respective MRL values. More extensive studies coveringdifferent regions of Haryana state are suggested to get a clearidea of the magnitude of vegetable contamination with pesticideresidues.     

Economic and Spatial Impacts of an Existing Reserve Network on Future Augmentation

An optimization model for land reservation was developed that explicitly selects parcels in the most compact or contiguous manner possible while meeting habitat requirements and a budget limitation. The model was used to compare the effects of an existing reserve network on future parcel spatial locations and total cost. Using habitat and land value data from Josephine County, Oregon, it was found that a system of existing reserves created by various policies and overseen by different agencies can decrease future reserve compactness and contiguity, and increase total cost. This work suggests that coordinated planning can result in more efficient conservation efforts for less cost.     

Seasonal variations in nickel and vanadium in Mont Blanc snow and ice dated from the 1960s and 1990s

Ni and V have been determined in snow and ice collected at a high altitude location (Col du D?me) near the summit of Mont Blanc on the French-Italian border; dated from the 1960s and 1990s. Ni and V were simultaneously determined by inductively coupled plasma sector field mass spectrometry. Measured concentrations range from 6 to 700 pg g(-1) and 4 to 1,100 pg g(-1) for Ni and V, respectively. The results show pronounced seasonal variations in the concentrations of both metals, with high concentration values in summer layers and much lower values for winter layers. These seasonal variations are linked especially with the existence of inversion layers during winter months. Ni and V concentrations in excess of the contributions from rock and soil dust (Ni(excess), V(excess)) appear to be mainly associated with anthropogenic inputs, with pronounced seasonal variations. Large variations in the V(excess)/Ni(excess) ratio are observed, with a higher ratio in summer than in winter. This shows differences in anthropogenic inputs at Col du D?me during the different parts of the year. The above ratio was compared with the corresponding ratios for oil combustion from stationary sources and the exhaust from gasoline and diesel engines. It appears that Ni and V concentrations at Col du D?me are probably the result of changing combinations of contributions from oil combustion for power generation, industrial and residential uses, on one side, and automobile and truck traffic, on the other side, with possibly a significant contribution from Ni smelters in Russia during winter months.     

Pollen allergy related to the area of residence in the city of Córdoba,south-west Spain

The aim of this study was to analyse the relationship between the distribution of hay-fever patients in the city of Córdoba, south-western Iberian Peninsula, and the specific atmospheric biological content originating from local sources. Four different districts were established in the metropolitan area of the city, according to vegetational and urbanistic characteristics. Air samples were taken in each area using portable Hirst-type samplers (Lanzoni VPPS 1000) and the spectrum of biological content was defined. Patients attending the Allergy Unit at Córdoba Teaching Hospital in 2000 with allergic rhinitis and/or asthma, and displaying a positive reaction to aeroallergen extracts, were distributed within the areas as a function of their district of residence. Aerobiological results revealed differences in pollen content between areas, in terms of both quantity and number of pollen types recorded. These differences were largely due to proximity to rural areas, prevalence of pollen from typically urban species and the possible effect of urban architecture as a barrier to the dispersal/ concentration of particles and other pollutants. Patients were not uniformly distributed within the city. The majority lived in districts in which pollen from rural species was mixed with pollen from ornamentals. Patients living in typically urban districts displayed a higher prevalence of allergy to pollen from ornamentals. It is concluded that a high degree of exposure to the same environment may influence the development of sensitisation to the particular pollen load associated with that area.     

Should foliar cadmium concentrations be expressed on a dry weight or dry ash weight basis?

Foliar analysis is a valuable tool for evaluating the pollution status of forests. However, the use of foliar diagnosis in large-scale surveys is a complicated process owing to the high variability within the crown. The method used to express foliar concentrations has often been found to diminish the variability. The effect of the method used to express element concentrations on the spatial variability of cadmium (Cd) in the leaves of crack willow (Salix fragilis L.) was investigated by sampling the leaves of one willow at 292 locations in the crown, each sampling location having a volume of 0.027 m3 (0.3 m x 0.3 m x 0.3 m). Cadmium showed a distinct spatial trend in the crown of the tree. Concentrations as low as 2.4 mg kg(-1) dry weight (DW) or 23.1 mg kg(-1) dry ash weight (DAW) were obtained in the top of the crown, and 10.6 mg kg(-1) DW or 73.0 mg kg(-1) DAW in the bottom of the crown. The lower relative standard deviation and weaker correlation with the sampling height support the use of DAW in large-scale surveys especially. The lower variability of the DAW Cd concentration makes this variable less sensitive to fluctuations caused by differences in growing conditions and sampling methodology. However, the majority of publications in this field report metal concentrations on a DW basis. Therefore, the restrictions set on the use of results expressed on a DAW basis in large-scale surveys of foliar metal concentrations have to be offset against the advantages offered by a reduction of the variability in metal concentrations.     

Chromium speciation and fractionation in ground and surface waters in the vicinity of chromite ore processing residue disposal sites

Chromium concentrations of up to 91 mg l(-1) were found by ICP-OES for ground water from nine boreholes at four landfill sites in an area of S.E. Glasgow/S. Lanarkshire where high-lime chromite ore processing residue (COPR) from a local chemical works had been deposited from 1830 to 1968. Surface water concentrations of up to 6.7 mg l(-1) in a local tributary stream fell to 0.11 mg l(-1) in the River Clyde. Two independent techniques of complexation/colorimetry and speciated isotope dilution mass spectrometry (SIDMS) showed that Cr was predominantly (>90%) in hexavalent form (CrVI) as CrO4(2-), as anticipated at the high pH (7.5-12.5) of the sites. Some differences between the implied and directly determined concentrations of dissolved CrIII, however, appeared related to the total organic carbon (TOC) content. This was most significant for the ground water from one borehole that had the highest TOC concentration of 300 mg l(-1) and at which < 3% of Cr was in the form of CrVI. Subsequent ultrafiltration produced significant decreases in Cr concentration with decreasing size fractions, e.g. <0.45 microm, < 100 kDa, <30 kDa and < 1 kDa by the tangential-flow method. As this appeared related more to concentrations of humic substances than of TOC per se, horizontal bed gel electrophoresis of freeze-dried ultrafilter retentates was carried out to further characterise the CrIII-organic complex. This showed for the main Cr-containing fraction, 100 kDa-0.45 microm, that the Cr was associated with a dark brown band characteristic of organic (humic) matter. Comparison of gel electrophoresis and FTIR results for ultrafilter retentates of ground water from this borehole with those for a borehole at another site where CrVI predominated suggested the influence of carboxylate groups, both in reducing CrVI and in forming soluble CrIII-humic complexes. The implications of this for remediation strategies (especially those based on the addition of organic matter) designed to reduce highly mobile and carcinogenic Cr(VI)O4(2-) to the much less harmful CrIII as insoluble Cr(OH)3 are discussed.     

Distribution of Chlorinated Organic Pollutants in Harbor Sediments of Livorno (Italy): A Multivariate Approach to Evaluate Dredging Sediments

Dredging is a very important procedure for harbor management. InItaly the guidelines for the offshore dumping of dredged materials are issued by the Ministry of Environment. Theydescribed a few steps of dredging activities, such as thesampling strategy, but do not deal with limits or guide-valuesfor the chemical, physical and biological composition of theresulting sediments. The quality of dredged materials is mainlydependent on the presence of inorganic and organic pollutants.In particular, polychlorinated biphenyls (PCBs) and organo-chlorinated pesticides are seen as a high priority inmarine environment by international organizations because oftheir persistence, toxicity and bioaccumulation capacity.In this article the presence of some PCBs and organo-chlorinatedpesticides in sediment samples collected from the harbor ofLivorno (Northern Tyrrhenian Sea) was investigated. Theconcentration of HCHs, Aldrin, Chlordanes, DDEs, DDTs, and PCBsin 12 representative sites ranged between <1 g kg^–1and 95, 19, 32, 35, 107, and 111 g kg^–1, respectively.The application of univariate and multivariate statisticaltechniques, such as linear regression analysis and principalcomponent analysis, to the experimental data showed a differentdistribution of PCBs in the two sediment layers. On thecontrary, the vertical distribution of the other investigatedpollutants was more homogeneous and affected by randomvariability. The multivariate approach was an important tool to establish more rational criteria for the management of dredged materials.     

Preliminary air pollution monitoring in San Miguel, Buenos Aires

Passive diffusion samplers were employed in San Miguel(Buenos Aires Metropolitan Area) for a preliminary airpollution monitoring. The highest loads were observedin downtown, compared with an urban background site.Total suspended particulate matter (TSPM) varied from0.257 to 0.033 mg cm^-2 month^-1; dust was examinedfor particle nature and size distribution. A similartrend was observed for nitrogen dioxide (NO₂) andTSPM spatial distribution, suggesting that traffic isthe major pollution source. Sulphur dioxide (SO₂)values were low and rather homogeneous. Levels for theinvestigated pollutants are below EPA's guide linevalues. Geographic (flat area, near to Rio de LaPlata) and climatologic factors (rainfalls andvariable wind directions) contribute to disperse pollutants.